Spring hinges for continuously urging doors into a closed position are well known and have long been employed in the prior art. Many present building codes require automatic door closing devices in certain locations of use. Depending upon the size and weight of the door, as well as the environmental conditions to which it may be exposed, e.g., wind drafts and the like, it is generally desirable that spring hinge automatic door closing devices be capable of adjustment to vary the torsional force on the spring and the corresponding force of closure exerted by the spring hinge on the door which it supports.
Certain adjustable spring hinge constructions typically comprise a pair of opposed hinge leaves having hollow knuckle portions axially aligned to form a hinge barrel containing a torsion spring therein. Pintles located in each end of the hinge barrel extend through adjacent knuckles to maintain them in axial alignment and operatively engage an adjacent end of the torsion spring to fix the same against relative rotation to a knuckle of each respective hinge leaf. Torsional force of the spring may thus be established and adjusted by rotational positioning of one of the end pintles about the axis of the hinge barrel, with a stop pin being received through a pin opening in the wall of the knuckle which aligns with a selected pin opening in the pintle to fix the pintle against rotation. Generally, adjustable rotation of the pintle of such spring hinges is accomplished by means of a hex wrench or screwdriver which must be inserted into a preformed opening extending axially into the exposed end of the pintle to rotate the same, or a capstan type hub is provided on the exposed end of the pintle outside the knuckle for receipt of an adjusting rod to rotate the pintle to bring a selected pintle stop pin opening into alignment with the knuckle opening or hinge leaf edge. Adjustable spring hinges are illustrated in the following prior art patents: U.S. Pat. No. 6,112; U.S. Pat. No. 1,954,934; U.S. Pat. No. 3,825,973; U.S. Pat. No. 3,898,708; U.S. Pat. No. 3,965,533; U.S. Pat. No. 4,043,001; and French Pat. No. 2,305,573.
Generally such spring hinge constructions of the type described may be pretensioned to provide a desired closure force, or they may be adjusted after installation on a door to provide the proper closure force for the size, weight and environmental conditions of use of the door. Due to space limitations in the location of use of the door hinge, such as in areas close to corners of rooms or with doors have heavy or protruding door frame molding, it is often difficult to accurately view and rotatably position the adjusting pintle by use of a screwdriver or hex wrench inserted into an axial opening in the end of the pintle. Similarly, the use of a protruding capstan on the end of the pintle for rotational adjustment necessarily results in increasing the size or length of the hinge beyond that necessary for support of the door.
In many door hinge constructions, it is also often desirable to provide anti-friction surfaces between the relatively moving metal parts of the door hinge, such as between pintle and knuckle surfaces, and between adjacent knuckle surfaces of opposite leaves of the hinge, to facilitate smooth relative movement of the hinge leaves about the hinge barrel axis during swinging of the door. In such pintle adjusting spring door hinge constructions, it is often difficult to provide ready access to rotational adjustment of the pintle as well as an anti-friction surface for movement of the hinge, while still ensuring that the adjustable pintle remains firmly secured in the end of the hinge barrel, regardless of the orientation of the hinge.